Liquid crystal display device

ABSTRACT

To provide a liquid crystal display device capable of controlling deterioration of contrast even in the case where an opening is formed in an organic flattened film and the film has unevenness. In the liquid crystal display device that includes a TFT substrate, a CF substrate, and liquid crystal sandwiched between the TFT substrate and the CF substrate and that drives the liquid crystal with a lateral electric field, the TFT substrate has the organic flattened film in which a through hole for contacting a source electrode of the TFT and a pixel electrode and a sectional shape of the through hole is asymmetrical between a side on which the pixel electrode extends and the other side.

CLAIM OF PRIORITY

The present application claims priority from Japanese patent applicationJP 2013-230505 filed on Nov. 6, 2013 the content of which is herebyincorporated by reference into this application.

FIELD OF THE INVENTION

The present invention relates to a liquid crystal display device.

BACKGROUND OF THE INVENTION

Since the liquid crystal display device is flat and lightweight, itsuses have spread in various fields from large display devices such as TVto small display devices such as a cellular phone and a digital stillcamera (DSC). In the liquid crystal display device, a TFT substrate inwhich pixels each having a pixel electrode, a thin film transistor(TFT), etc. are formed in a matrix and a counter substrate (CFsubstrate) that faces the TFT substrate and in which color filters etc.are formed in places corresponding to the pixel electrodes of the TFTsubstrate are arranged, and liquid crystal is sandwiched between the TFTsubstrate and the counter substrate.

Usually, display of a liquid crystal display device is performed bychanging an alignment direction of liquid crystal molecules sandwichedby these substrates by applying an electric filed thereto and usingvariation of optical characteristics of a liquid crystal layer caused byit. The alignment direction of the liquid crystal molecules when noelectric filed is applied is defined by, for example, an alignment filmhaving been subjected to a rubbing treatment on its surface. The rubbingis disclosed in, for example, Japanese Unexamined Patent ApplicationPublication No. 2010-2594.

SUMMARY OF THE INVENTION

In liquid crystal display devices, demands of wide viewing angle andhigh contrast are high. Thereupon, a situation of contrast has beenexamined using a lateral electric field mode liquid crystal displaydevice capable of providing the wide viewing angle. A plan view (partialperspective view) of a pixel region of the liquid crystal display devicethat was examined is shown in FIG. 1A, an outline sectional view in aline A-A′ of FIG. 1A is shown in FIG. 7A, and an outline sectional viewin a line B-B′ of FIG. 1A is shown in FIG. 7B. Gate wiring 115 serves asa scanning signal line, and drain wiring 110 is a video signal line(FIG. 1A). A pixel electrode 120 is formed of ITO that is a transparentelectrode, is a comb-like shaped electrode whose tip ends are closed(FIG. 1A), and is connected to a source electrode 121 through an openingprovided on an organic flattened film 107 (FIG. 7A). The sourceelectrode 121 is connected to a source region of a semiconductor layer125 (FIG. 7B). Moreover, a common electrode 130 for forming a lateralelectric field in a liquid crystal layer between the pixel electrode 120and itself is formed on the organic flattened film 107 (FIG. 7A).Incidentally, names of a source, a drain, etc. are expedient, and whenone of them is called the source, the other can be called the drain.

A configuration of a TFT substrate 100 will be explained. A first groundfilm 102 is formed of SiN on a glass substrate 101, and a second groundfilm 103 is formed of SiO₂ on it.

The semiconductor layer 125 is formed on the second ground film 103(FIG. 7B). Here, the semiconductor layer 125 is formed of poly-Si. Thepoly-Si film is formed by first depositing an a-Si film by CVD etc. andannealing this a-Si film by irradiation of laser light. A firstinsulating film (gate insulating film) 104 is formed on thesemiconductor layer 125. The gate wiring 115 that is a scanning signalline is formed on the gate insulating film 104 (FIG. 7B).

After the gate wiring 115 is formed, phosphor or boron is doped by ionimplantation into the semiconductor layer 125, which is made to be aconductor by giving conductivity to the semiconductor layer 125 otherthan a portion thereof covered with the gate wiring 115. Subsequently, asecond insulating film (first interlayer insulating film) 105 is formedto cover the gate wiring 115. After an opening is formed in the stackedfilms of the first insulating film 104 and the second insulating film sothat a source region and a drain region (not illustrated) of thesemiconductor layer 125 may be exposed, drain wiring 110 that is thevideo signal line, the source electrode 121, etc. are formed on thesecond insulating film (first interlayer insulating film) 105 (FIG. 7A).The drain wiring 110 that is the video signal line and the sourceelectrode 121 are simultaneously formed in the same layer.

A third insulating film (inorganic passivation film) 106 comprised ofSiN is formed to cover the video signal line 110 and the sourceelectrode 121 (FIG. 7A). The flattened film 107 made of an organic filmis formed to cover the inorganic passivation film 106. Since the organicflattened film 107 needs to be flattened in its film top part, it isformed as thick as 1 μm to 3 μm.

Moreover, the organic flattened film 107 also has a role as apassivation film for protecting the TFT. The organic flattened film 107is formed of a photosensitive film (photoresist film) and enables athrough hole to be formed by performing etching and development, withoutforming a further photoresist film.

On the organic flattened film 107, the common electrode 130 having anopening that exposes a through hole portion and a fourth insulating film(second interlayer insulating film) 108 having an opening that furtherexposes the through hole portion are formed. Subsequently, an openingthat exposes the source electrode 121 is formed in the third insulatingfilm, and the pixel electrode 120 and further an alignment film 109 areformed. Next to this, an alignment direction of the alignment film 109is specified by an alignment process by rubbing.

The liquid crystal display device was manufactured by stacking a CFsubstrate (counter substrate) 200 with a photo spacer 210 formed facingthe above-mentioned TFT substrate on it (FIG. 7A), sealing the liquidcrystal between these substrates, and attaching a polarizing plate, aback light, a touch panel, a protective case, etc. thereon if needed. Asa result of evaluating a contrast in this liquid crystal display device,it turned out that the contact lowered, especially, in the vicinity ofthe through hole for contacting the pixel electrode and the sourceelectrode.

An object of this invention is to provide a liquid crystal displaydevice capable of controlling deterioration of the contrast even in thecase where an opening is formed in the organic flattened film and thefilm has unevenness.

Means for Solving the Problem

As one embodiment for attaining the above-mentioned object, the liquidcrystal display device is configured to be a liquid crystal displaydevice that is comprised of a first substrate having a TFT and thealignment film, a second substrate having a spacer, and the liquidcrystal sandwiched between the first substrate and the second substratewhose gap is specified by the spacer and that drives the liquid crystalwith a lateral electric field, characterized in that the first substratehas the organic flattened film in which the through hole for contactingthe source electrode of the TFT and the pixel electrode for forming thelateral electric field, and a sectional shape of the through hole isasymmetrical to a central axis of the through hole between a sidethereof on which the pixel electrode extends and the other side thereof.

Moreover, the liquid crystal display device is configured to be a liquidcrystal display device that is comprised of the first substrate havingthe TFT and the alignment film, the second substrate having the spacer,and the liquid crystal sandwiched between the first substrate and thesecond substrate whose gap is specified by the spacer, characterized inthat the first substrate has the organic flattened film in which thethrough hole is formed and that in a side wall upper part of the throughhole, a taper angle of the through hole is small on a side thereof onwhich the pixel electrode extends compared with that on the other sideof thereof in order to reduce the non-rubbing region in the taper partof the through hole.

Effects of the Invention

According to the present invention, even in the case where the openingis formed in the organic flattened film and the film has unevenness, itis possible to provide the liquid crystal display device capable ofcontrolling the deterioration of the contrast.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is an outline plan view (partial perspective view) of a pixelpart of a liquid crystal display device that the inventors haveexamined;

FIG. 1B is a sectional view of an organic flattened film in a line A-A′shown in FIG. 1A;

FIG. 1C is a sectional view of the organic flattened film in a line B-B′shown in FIG. 1A;

FIG. 2A is an outline plan view (partial perspective view) showing oneexample of the pixel part of the liquid crystal display device accordingto a first embodiment of the present invention;

FIG. 2B is a sectional view of the organic flattened film in the lineA-A′ shown in FIG. 2A;

FIG. 2C is a sectional view of the organic flattened film in the lineB-B′ shown in FIG. 2A;

FIG. 3 is a sectional view of the organic flattened film in the lineB-B′ shown in FIG. 2A;

FIG. 4 is a diagram for explaining an organic flattened film in a liquidcrystal display device according to a second embodiment of the presentinvention, and is a sectional view in the line B-B′ shown in FIG. 2A;

FIG. 5 is a diagram for explaining an organic flattened film in a liquidcrystal display device according to a third embodiment of the presentinvention, and is a sectional view in the line B-B′ shown in FIG. 2A;

FIG. 6 is a diagram for explaining an organic flattened film in a liquidcrystal display device according to a fourth embodiment of the presentinvention, and is a sectional view in the line B-B′ shown in FIG. 2A;

FIG. 7A is an outline sectional view in the line A-A′ shown in FIG. 1Aor FIG. 2A;

FIG. 7B is an outline sectional view in the line B′-B shown in FIG. 1A;

FIG. 7C is an outline sectional view in the line B′-B shown in FIG. 2A;

FIG. 8A is an outline sectional view for explaining a processing step(organic flattened film application step) of a through hole for contactof the organic flattened film in the liquid crystal display deviceaccording to the first embodiment of the present invention;

FIG. 8B is an outline sectional view for explaining a processing step(exposure step) of the through hole for contact of the organic flattenedfilm in the liquid crystal display device according to the firstembodiment of the present invention;

FIG. 8C is an outline sectional view for explaining a processing step(development step) of the through hole for contact of the organicflattened film in the liquid crystal display device according to thefirst embodiment of the present invention; and

FIG. 9 is an outline side view for explaining an alignment process byrubbing.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

In a manufactured liquid crystal display device, since a contrast lowersin the vicinity of a through hole for contacting a pixel electrode and asource electrode, inventors paid their attention to the through hole forcontact, especially, an organic flattened film that occupied a most partof its film thickness. FIG. 1B shows a sectional view of the organicflattened film in the line A-A′ of FIG. 1A, and the FIG. 1C shows asectional view of the organic flattened film in the line B-B′. From thissectional shape, it was inferred that deterioration of the contrastoccurred because an organic flattened film 107 became a non-rubbingregion 251 over a range from the taper top end of the through hole forcontact to its inside, which caused light leakage. A reference numeral250 denotes a rubbing region. Thereupon, when the liquid crystal displaydevice was set to perform black display, a phenomenon in which aperiphery part of the through hole on the pixel element electrode sideshone white (black luminance is high) was recognized. That is, it turnedout that an alignment film in this region was not aligned by analignment process by rubbing. If this region shining white is shaded, itwill lead to lowering of an opening ratio of the pixel, which will benot suitable, and therefore, the inventors have examined reducing thelight leakage by other means. The alignment process by rubbing isperformed, as shown in FIG. 9, by making a roller 400 around which arubbing cloth was wound rotate in an arrow direction 402 while moving aTFT substrate 100 on which an alignment film 109 was formed to an arrowdirection 410. Since the alignment is specifically performed by makingbristles 401 of the rubbing cloth rub the alignment film as shown in anenlarged view of FIG. 9, it seemed that larger the tilt angle α of thethrough hole taper part, the taper part became difficult to be rubbed.Then, when a taper shape, especially a taper shape at the taper top endwas controlled, it was checked that by making small a tilt angle of thethrough hole at the taper top end, reduction of a non-rubbing region wasable to be attained. However, if the tilt angle at the taper top end ofthe through hole is made small, the whole periphery of the through holewill have the same taper angle (becoming axially symmetrical to thecenter axis omnidirectionally). That case is not desirable becausesurface flatness in a gate wiring direction on a side of the TFTsubstrate that receives a photo spacer 210 shown in FIG. 7A is impaired.Especially, as miniaturization advances, the width of the organicflattened film becomes smaller, which poses a problem. Therefore, in thepresent invention, the taper shape is controlled only in a desireddirection (for example, only the pixel side (a left-hand side of FIG.3)).

Hereinafter, the present invention will be described in detail usingembodiments. Incidentally, the same reference numeral represents thesame component.

First Embodiment

A first embodiment of the present invention will be explained using FIG.2A to FIG. 2C, FIG. 4 to FIG. 6, FIGS. 7A and 7C, and FIG. 8A to FIG.8C.

FIG. 2A shows an outline plan view (partial perspective view) of a pixelpart of the liquid crystal display device according to this embodiment,FIG. 2B shows an outline sectional view of the organic flattened film inthe line A-A′ of FIG. 2A, and FIG. 2C shows an outline sectional view ofthe organic flattened film in the line B-B′ of FIG. 2A. In the line A-A′direction in which the photo spacer is arranged, a taper angle of thethrough hole is maintained up to the taper top end. On the other hand,on the B side of the line B-B′ in which the pixel is arranged, the taperis formed so that the taper angle of the through hole may become smallat the taper top end. Thereby, since a wider range of a taper region Lis aligned in the alignment process by rubbing (FIG. 2A, FIG. 2C), thenon-rubbing region 251 can be reduced.

Next, a method of making the taper angle of the through holeasymmetrical depending on its direction will be explained using FIG. 8Ato FIG. 8C. First, a photosensitive organic flattened film (photoresistfilm) about 3-μm thick is formed on an underlying substrate 150 on whichthe TFT etc. are formed (FIG. 8A). Subsequently, the photosensitiveorganic flattened film is exposed with exposure light 320 using aphotomask (half-tone mask) 310 whose transmittance of the exposure lightin a region corresponding to the taper part in a direction in which thetilt angle is intended to be made small is varied (FIG. 8B).Subsequently, the through hole is formed by performing treatments ofdevelopment, cleaning, etc. (FIG. 8C). A spatial relationship of a tapercontrol part 160 and a half-tone mask is as shown in FIG. 8C. A range inwhich the taper shape is controlled is specified to be one ranging fromthe through hole and a bending portion of a pixel electrode 120 as areference (refer to FIG. 2A), and is limited to a region that causes noinfluence in display. Although a photoresist of positive type was usedin this embodiment, the photoresist is not limited to this.Incidentally, since the amount of sensitization in a desired region ofthe organic flattened film can be varied by varying the transmittance ofthe exposure light in a region corresponding to the taper part in adirection in which the tilt angle is intended to be made small, thetaper part can be not only in a shape shown in FIG. 3 but also in shapesas shown in FIG. 4 to FIG. 6. However, the structure show in FIG. 3 iseasy to manufacture. Although a depth of the taper shape to be formeddiffers depending on conditions of the alignment process, it can beadjusted arbitrarily in accordance with the conditions.

Next, a configuration of the through hole for contact of the liquidcrystal display device according to this embodiment will be explainedusing FIG. 7A and FIG. 7C. FIG. 7A is an outline sectional view in theline A-A′ of FIG. 2A and FIG. 7C is an outline sectional view in theline B-B′ shown in FIG. 2A.

A first ground film 102 is formed of SiN on a glass substrate 101 and asecond ground film 103 is formed of SiO₂ on it. The first ground film102 and the second ground film 103 are both formed in order to protect asemiconductor layer 125 of the TFT from impurities that deposit from theglass.

The semiconductor layer 125 is formed on the second ground film 103(FIG. 7C). In this embodiment, the semiconductor layer 125 is formed ofpoly-Si. The poly-Si film is formed by first depositing an a-Si film byCVD etc. and annealing this a-Si film by irradiation of laser light. Afirst insulating film (gate insulating film) 104 is formed on thesemiconductor layer 125. Gate wiring 115 that is a scanning signal lineis formed on the gate insulating film 104 (FIG. 7C).

After the gate wiring 115 is formed, the semiconductor layer 125 is madeto be a conductor by doping phosphor, boron, or the like by ionimplantation to the semiconductor layer 125 and giving conductivity tothe semiconductor layer 125 other than the portion covered with the gatewiring 115. Subsequently, a second insulating film (first interlayerinsulating film) 105 is formed to cover the gate wiring 115. After anopening is formed in the stacked films of the first insulating film 104and the second insulating film so that a source region and a drainregion (not illustrated) of the semiconductor layer 125 may be exposed(FIG. 7A), drain wiring 110 that is a video signal line, a sourceelectrode 121, etc. are formed on the second insulating film (firstinterlayer insulating film) 105. The drain wiring 110 that is the videosignal line and the source electrode 121 are simultaneously formed inthe same layer.

A third insulating film (inorganic passivation film) 106 comprised ofSiN is formed to cover the video signal line 110 and the sourceelectrode 121 (FIG. 7A). A role of the inorganic passivation film 106 isto protect the TFT. The flattened film 107 made of the organic film isformed to cover the inorganic passivation film 106. The organicflattened film 107 is formed in order to maintain flatness of the commonelectrode 130 or the pixel electrode 120. Since the organic flattenedfilm 107 needs to be flattened in its film top part, it is formed thickto be 1 μm to 3 μm.

Moreover, the organic flattened film 107 also has a role as apassivation film for protecting the TFT. The organic flattened film 107is formed of a photosensitive film such as an acrylic resin and apolyimide resin, and enables the through hole to be formed withoutforming a resist film separately. The through hole is formed asexplained using FIG. 8A to FIG. 8C, and has an asymmetrical form suchthat an angle of a taper top end of the through hole becomes small in apixel electrode direction compared with those of other directions.

On the organic flattened film 107, the common electrode 130 having anopening that exposes the through hole and further a fourth insulatingfilm (second interlayer insulating film) 108 having an opening thatexposes the through hole are formed. The second interlayer insulatingfilm 108 is formed in order to maintain insulation between the commonelectrode 130 and the pixel electrode 120. Subsequently, an opening fromwhich the source electrode 121 exposes is formed in the third insulatingfilm, and the comb-like shaped pixel electrode 120 and further thealignment film 109 are formed on it. Next to this, an alignmentdirection of the alignment film 109 is specified by the alignmentprocess by rubbing. Since the through hole of the organic flattened filmwas configured so that an angle of the taper top end of the through holemight be made small at a side thereof where the pixel electrode extendscompared with the other side thereof, it is possible to reduce thenon-rubbing region by an amount of the region L (FIG. 7C). Moreover,since the taper angle of the through hole was large in the line A-A′direction (a direction going along the gate wiring that is the scanningsignal line) of FIG. 2A, an upper surface of the organic flattened filmwas able to be flattened in a wide range, and it was possible to arrangethe photo spacer for holding a gap of the TFT substrate and the CFsubstrate in a flat region on the TFT substrate.

The liquid crystal display device was manufactured by stacking a CFsubstrate 200 with the photo spacer 210 formed facing theabove-mentioned TFT substrate on it (FIG. 7A), sealing the liquidcrystal between these substrates, and attaching a polarizing plate, aback light, a touch panel, a protective case, etc. thereon. As a resultof evaluating the contrast in this liquid crystal display device, it waspossible to reduce the light leakage in the vicinity of the through holefor contacting the pixel electrode and the source electrode, to reducethe black luminance, and to control the deterioration of the contrast.Moreover, it was possible to acquire a wide viewing angle by adopting alateral electric field mode.

From the above, according to this embodiment, even in the case where theopening is formed in the organic flattened film and the film hasunevenness, it is possible to provide the liquid crystal display devicecable of controlling the deterioration of the contrast by making smallthe angle of the taper top end of the opening in the pixel electrodedirection compared with those in the other directions. Moreover, bymaking large the angle of the taper top end of the opening in the gatewiring direction compared with that in the pixel electrode direction, itis possible to arrange the photo spacer in the flat region on the TFTsubstrate.

Second Embodiment

A second embodiment of the present invention will be described usingFIG. 4. Incidentally, any matter that was described in the firstembodiment and is not described in this embodiment can be applied tothis embodiment unless there are special circumstances. In thisembodiment, a structure shown in FIG. 4 was used as that of the organicflattened film.

As a result of adopting the same configuration as that of the firstembodiment except the structure of the organic flattened film, it waspossible to reduce the non-rubbing region because the through hole ofthe organic flattened film was configured so that the angle of the tapertop end of the through hole might be made small in a direction in whichthe pixel electrode extends compared with those of the other directions.Moreover, since in the direction going along the gate wiring that is thescanning signal line, the taper angle of the through hole is large, theupper surface of the organic flattened film was able to be flattened ina wide range, and it was possible to arrange the photo spacer forholding the gap of the TFT substrate and the CF substrate in the flatregion on the TFT substrate. Moreover, by configuring the taper part ofthe through hole to have a two-stage structure of a high-angle tilt anda low-angle tilt, it was possible to make small the variation of theboundary between the rubbing region 250 and the non-rubbing region 251compared with the first embodiment having a configuration in which thetilt angle varied continuously.

As a result of manufacturing the liquid crystal display device bystacking the CF substrate 200 with the photo spacer 210 formed facingthe above-mentioned TFT substrate on it (FIG. 7A), sealing the liquidcrystal between these substrates, and attaching the polarizing plate,the back light, the touch panel, the protective case, etc. thereon andevaluating its contrast, it was possible to reduce the light leakage inthe vicinity of the through hole for contacting the pixel electrode andthe source electrode, to reduce the black luminance, and to control thedeterioration of the contrast. Moreover, it was possible to achieve thewide viewing angle by adopting the lateral electric field mode. From theabove, according to this embodiment, it is possible to acquire the sameeffect as that of the first embodiment. Moreover, it is possible toreduce the variation of the non-rubbing region compared with the firstembodiment.

Third Embodiment

A third embodiment of the present invention will be described using FIG.5. Incidentally, any matter that was described in the first embodimentand is not described in this embodiment can be applied to thisembodiment unless there are special circumstances. In this embodiment, astructure shown in FIG. 5 is used as that of the organic flattened film.

As a result of manufacturing it in the same manner as in the firstembodiment except the structure of the organic flattened film, it waspossible to reduce the non-rubbing region because in the through hole ofthe organic flattened film, the angle of the taper top end of thethrough hole in a direction in which the pixel electrode extended wasmade small compared with those in the other directions. Moreover, sincein the direction going along the gate wiring that is the scan signalline, the taper angle of the through hole is large, the upper surface ofthe organic flattened film was able to be flattened in a wide range, andit was possible to arrange the photo spacer for holding the gap of theTFT substrate and the CF substrate in the flat region on the TFTsubstrate. Moreover, by configuring the taper part of the through holeto have the virtually two-stage structure of the high-angle tilt and thelow-angle tilt in the direction in which the pixel electrode extends, itwas possible to make small the variation of the boundary of the rubbingregion 250 and the non-rubbing region compared with the first embodimenthaving the configuration in which the tilt angle varied continuously.

The liquid crystal display device was manufactured by stacking the CFsubstrate 200 with the photo spacer 210 formed facing theabove-mentioned TFT substrate on it (FIG. 7A), sealing the liquidcrystal between these substrates, and attaching the polarizing plate,the back light, the touch panel, the protective case, etc. thereon, andits contrast was evaluated. As a result, it was possible to reduce thelight leakage in the vicinity of the through hole for contacting thepixel electrode and the source electrode, to reduce the black luminance,and to control the deterioration of the contrast. Moreover, it waspossible to achieve the wide viewing angle was by adopting the lateralelectric field mode. From the above, according to this embodiment, it ispossible to acquire the same effect as that of the first embodiment.Moreover, it is possible to reduce the variation of the non-rubbingregion compared with the first embodiment.

Fourth Embodiment

A fourth embodiment of the present invention will be described usingFIG. 6. Incidentally, any matter that was described in the firstembodiment and is not described in this embodiment can be applied tothis embodiment unless there are special circumstances. In thisembodiment, a structure shown in FIG. 6 was used as that of the organicflattened film.

As a result of manufacturing this embodiment in the same manner as inthe first embodiment except the structure of the organic flattened film,it was possible to reduce the non-rubbing region because in the throughhole of the organic flattened film, the angle of the taper top end inthe direction in which the pixel electrode extends was made small ascompared with those in the other directions. Moreover, since the taperangle of the through hole is large in the direction going along the gatewiring that is the scanning signal line, the upper surface of theorganic flattened film was able to be flattened in a wide range, and itwas possible to arrange the photo spacer for holding the gap of the TFTsubstrate and the CF substrate in the flat region on the TFT substrate.Moreover, by configuring the taper part of the through hole to have thevirtually two-step structure of the high-angle tilt and the low-angletilt in the direction in which the pixel electrode extends, it waspossible to make small the variation of the boundary between the rubbingregion 250 and the non-rubbing region 251 as compared with the firstembodiment having the configuration in which the tilt angle variedcontinuously.

The liquid crystal display device was manufactured by stacking the CFsubstrate 200 with the photo spacer 210 formed facing theabove-mentioned TFT substrate on it (FIG. 7A), sealing the liquidcrystal between these substrates, and attaching the polarizing plate,the back light, the touch panel, the protective case, etc., thereon andits contrast was evaluated. As a result, it was possible to reduce thelight leakage in the vicinity of the through hole for contacting thepixel electrode and the source electrode, to reduce the black luminance,and to control the deterioration of the contrast. Moreover, it waspossible to achieve the wide viewing angle by adopting the lateralelectric field mode. From the above, according to this embodiment, it ispossible to acquire the same effect as that of the first embodiment.Moreover, it is possible to reduce variation of the non-rubbing regioncompared with the first embodiment.

It should be noted that the present invention is not limited to theabove-mentioned embodiments, and various modifications are includedwithin the scope of the present invention. The embodiments describedabove are explained in detail in order to explain the present inventioncomprehensively, and are not necessarily limited to those having all theconfigurations explained above. For example, although the inorganicpassivation film 106 is provided in the embodiment, an embodiment mayhave a structure in which that film is not provided.

What is claimed is:
 1. A liquid crystal display device comprising: afirst substrate having a TFT and an alignment film; a second substratehaving a plurality of spacers; and liquid crystal sandwiched between thefirst substrate and the second substrate, wherein the first substratehas an organic film has a through hole for contacting a source electrodeof the TFT and a pixel electrode, and wherein a sectional shape of thethrough hole is asymmetrical to a central axis of the through holebetween at a side where the pixel electrode extends and at the otherside.
 2. The liquid crystal display device according to claim 1, whereina direction in which the pixel electrode extends and a direction inwhich a drain wiring of the TFT extends are mutually parallel, andwherein the direction in which the pixel electrode extends and adirection in which a gate wiring of the TFT extends intersect mutuallyperpendicularly.
 3. The liquid crystal display device according to claim1, wherein the spacers are arranged in a direction in which gate wiringof the TFT extends and on drain wiring of the TFT through the organicflattened film.
 4. The liquid crystal display device according to claim1, wherein the pixel electrode is in a comb-like shape that has a bentshape in the vicinity of the through hole, and wherein a range of theasymmetry goes as far as the bent shape of a comb teeth end of the pixelelectrode in plan view.
 5. The liquid crystal display device accordingto claim 1, wherein the alignment film is subjected to an alignmenttreatment by rubbing.
 6. A liquid crystal display device comprising: afirst substrate having a TFT and an alignment film; a second substratehaving a plurality of spacers; and liquid crystal sandwiched between thefirst substrate and the second substrate, wherein the first substratehas an organic film in which a through hole is formed, and wherein thethrough hole is such that in a side wall upper part, a side thereof onwhich the pixel electrode extends has a small taper angle compared withthe other side thereof.
 7. The liquid crystal display device accordingto claim 6, wherein the organic film is formed of a photoresist film,and wherein the through hole is formed by exposing the photoresist filmusing a half-tone mask.
 8. The liquid crystal display device accordingto claim 6, wherein the liquid crystal is driven by a lateral electricfield.
 9. The liquid crystal display device according to claim 8,wherein the through hole contacts a source electrode of the TFT and thepixel electrode for forming the lateral electric field.
 10. The liquidcrystal display device according to claim 9, wherein the spacer isarranged in a direction in which gate wiring of the TFT extends and ondrain wiring of the TFT through the organic flattened film.
 11. Theliquid crystal display device according to claim 6, wherein thealignment film is subjected to an alignment treatment by rubbing.